If you're looking for bang for the buck, you're much better off with 2x6970, as they'll perform similarly to 2x580. Or 2x570 for slightly less performance with $300 savings. If you're looking for the ultimate graphics rig, get 3x6970. It will smoke 2x580 for the same price.
The three optical drives is just plain senseless. I think I use mine like once every 3 months and I can't imagine anyone using 3 at once.